1. Field of the Invention
The instant disclosure relates to a ternary content-addressable memory; in particular, to a ternary content-addressable memory with read port and write assist.
2. Description of Related Art
A ternary content-addressable memory stores three types data including data “1”, data “0” and data “X”. Conventional ternary content-addressable memory comprises two search lines being a search-data pair, two memory cells being a storage-data pair, and a compare circuit. The compare circuit can be a NAND logic or a NOR logic, for example. The search-data pair (search lines) and the storage-data pair (two memory cells) are connected to the compare logic which discharges the match line when the logic status of the search-data pair is different from the data in the storage-data pair. As an example, referring to FIG. 1 showing a circuit diagram of a conventional 6T SRAM-based ternary content-addressable memory. A first SRAM 801 and a second SRAM 802 are connected to a compare circuit 803. The compare circuit 803 has a pair of NOR type compare logics. Another example is shown in FIG. 2. A first SRAM 901 and a second SRAM 902 constituting the storage-data pair are both a 4T SRAM cell. The compare circuit 903 is similar to the compare circuit 803 shown in FIG. 1. Research and development of new designs for the ternary content-addressable memory is still ongoing.